How does Katniss Everdeen change over time?
As the story begins, Katniss Everdeen, as portrayed by her first person narrative voice, is confident yet humble, brave yet somewhat foolhardy, honest and impulsive. She is aware that she may be chosen to participate in the Hunger Games, and she prepares for this by practicing her archery skills when she hunts for food. When her younger sister Primrose is chosen, Katniss and her mother are shocked because Prim is so young, and also worried, because Prim does not have the physical prowess or assertive character necessary to prevail in the Games. Katniss impulsively volunteers to take her sister's place. This act of bravery and self-sacrifice is perhaps the first step that puts Katniss on the road to becoming a hero of the people.
But we learn that the Hunger Games, far from being a game of chance and skill, are heavily manipulated by the government. Katniss eventually begins to understand this manipulation, and her behavior and personality adapt to help her meet the challenges she faces. She becomes less impulsive, as she understands that every move she makes and every word she speaks are under surveillance. This also forces her to become more calculating, and she learns she has to sometimes resort to lies and subterfuge. By manipulating those who are observing her, she finds ways to gain the support of the citizens and to play along with the government plot to groom her to be a hero and martyr.